Return-Path: Received: (qmail 11697 invoked from network); 26 Apr 2000 22:40:07 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by grants.core.plus.net.uk with SMTP; 26 Apr 2000 22:40:07 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 12kaLx-00033Z-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 26 Apr 2000 23:32:17 +0100 Received: from praseodumium.btinternet.com ([194.73.73.82]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 12kaLu-00033N-00 for rsgb_lf_group@blacksheep.org; Wed, 26 Apr 2000 23:32:14 +0100 Received: from [213.1.97.241] (helo=default) by praseodumium.btinternet.com with smtp (Exim 2.05 #1) id 12kaJC-00033A-00 for rsgb_lf_group@blacksheep.org; Wed, 26 Apr 2000 23:29:26 +0100 Message-ID: <000301bfafcf$3111bb80$f16101d5@default> From: "Alan Melia" To: "rsgb_lf_group" Subject: LF: High frequency-stability drive sources Date: Wed, 26 Apr 2000 21:08:16 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi there has been some discussion about stable drive sources for narrow band modes. One possible source that sometimes becomes available these days is a Pye/Philips unit which used to be used as the frequency source for quasi-synchronous radio communication systems, like the wide area coverage systems of the emergency and utility services. The unit model number is HS400 and it contains circuitry to lock a crystal to a 5MHz ovened standard oscillator (2 types with either a Toyo or a Racal unit). The stability available is a few parts in 10^9. I think these units are now obsolete so may become more easily available. They are a little large being 19in rack-mount units. If anyone does find one I have the technical details. 73 de Alan G3NYK Alan.Melia@btinternet.com